Carbonates of hydroxybenzoic acid esters



Patented Feb. 6, i940 I a I a 2 1 9 205,, 1

' CARBONATES F HYDROXYBENZOIC ACID s e ,s Ernest F. Grethejr and Russell B. Du van, Mid-,

land, lflichgassignors to The Dow Chemical Company, Midland; Mich, a corporation of Michigan. f v f No Drawing. Application May a1, 1938, 1 Serial No. 211,015 a a l a I GCIaims. ((11.260-463) 1 V This invention} concerns certain new chemical. ethyl salicylate, gamma hydronypropyl 4 -hy compounds, namely, the'carbonates of hydrox'ydroxybenzoate, beta-butoxyethyl 3-hydr'oxybenbenzoic acid esters; and in particular concerns zoate, etc'., in an inert solvent, such as acetone carbonates having the general formula: ormethyl ethyl ketone, and thereafter adding I l I phosgeneand a concentrated aqueous solution I f I of an alkali metal .hydroxide,j" whi1ecooling and B'( R)..0-o--. .00- RO ..R' o stirring the mixture. The reactants are. usually employed in the theoretical proportions, viz., l H one-half mole of phosgene andone mole of alkali l 10 wherein R representsan 'alkylene radical conmetal hydroxide per mole of ester, but other 10 tainingiat least 2 carbon atoms, R represents proportionsmay be employed if desired. Upon hydrogen or an alkyl radical, and n represents completionfof the reaction, the mixture is exan integer. X r tracted with a solvent such asbenzene, and the These compounds vary from high boiling, vis extract washed with water to remove the alkali cous liquids to crystalline solids. They are soluble metal chloride which is formed 'in thereaction. ll

or miscible in many organic solvents and do not ,-The carbonate product is obtained in substan readily decompose or become discolored. I They tially pure form by removin the solvent and any are useful as intermediates in the preparationof unreacted hydroxybenzoic ester by; fractionalother organic chemicals and as plasticizing agents, distillation under vacuum./ if desired, however, for vinyl lresin e. g., polystyrene, and cellulose the product may be further purified byfractional20 derivative, e. g.,bethyl cellulose, compositions. distillation under vacuum, or by crystallization Compositions plasticized with -:the aforesaid new from a suitable solvent, such as ethanol.

compounds are suitable for, use in theprepara- The following examples will illustrate several tion of artificial leather-,lacquersand other coata ways in which the principle of the invention has v ing compositions, films, molded plastics, etc. been-carried out, but are not to be construed as 25 The carbonates of hydroxybenzoic acid esters limiting the same: of the present class are prepared by reacting a" Example 1 glycol or glycol-ether ester of an hydroxybenzoic Y 1 l acid with phosgene in the presence of a caustic 105 grams mole) of-the beta-ethoxyethyl so alkali according to the method disclosed by. ester of sal y d wasjdijss lv d in 10 grams so Ernest F. Grether -in U. s! Patents Nos. 1,877,304 of acetone and-the solution was placedin a and 1,877,305. The reaction takes placeaccordthree-necked f a ,fittedwithfi stirrer, a p ing td-the following equation: ping funnel, and a gas inlet. The gas inlet exk tended just to the surface oi the liquid. The

solution was cooled to approximately 2 C. by 35 r v 0 114 l means of an ice bath, and 28fgrams (0.5 mole) 060a "of potassium hydroxide in theform of a 50 per l? cent aqueous "solution was slowly added from 2c m\ +2M0H+o0c12--. Q the dropping funnel, While at the same time a a 1 4o 0H 0- I current of-phosgenewas'passed into the reaction 4 (353/ mixture through the gas inlet. When all of the l \000R 1 I I potassium hydroxide hadbeen added and the I wherein R represents the g1yco1' r rglycopjeth-r solution became neutral, the supply of phosgene radicalfand Mrepresents an alkali mew; The was shut oil and the reaction; mixture was diluted -hydroxybenzoic acid esters employed] as Start; With ice Water. Th8 801111311011 Was extracted 45 j ing materials may be prepared by, Ies'terifying a e zene, was s v ra m with- Wa d glycol or an alkyl ether of a glycol with a the washed extract dried over anhydrous calcium! I hydroxybenzoic acid in accordance with the usual chloride. The benzene and a small amount of procedureemployed in preparing esters. unreacted beta-ethoxyethyljsalicylate were re- The reaction for-the production of the new: moved 'by distillation under reduced pressure'50 carbonates is preferably carried out by dissolving and the carbonate product was obtained as color. ithe hydroxybenzoic acid ester, e. g., beta -ethoxyless, high-boiling liquid having a mild, pleasant TES l -"ATYENT" omen: i

odor. The carbonate of beta-ethoxyethyl salicylate has a specific gravity of 1.2124 at /20 C., and an index of refraction It has the formula:

. Y Example 2 I 119 grams (0.50 mole) of beta-butoxyethyl 4-hydroxybenzoate was dissolved in acetone and solid. The solid product was filtered off, washed hydroxide as. in'Example 1.

' 20/4 0., and anindex of refraction,

cooled to 0-5 C. 28 grams of potassium hydroxide in the form of a 50 per cent aqueous solution and phosgene were introduced with stirring into the cooled acetone solution. When the reaction was complete, as indicated by the reaction mixture becoming neutral, the mixture was diluted with ice water, extracted with benzene and the benzene extract washed. Benzene and unreacted ester were distilled off under vacuum, and the product was obtained as a colorless oil which, upon cooling to room temperature, solidified to a white, wax-like'paste. alysis showed this'product to be the carbonate of beta-butoxyethyl 4 -hydroxybenzoate, having the formula: 1

Example 3 A solution of 91.0 grams (0.50 mole) of the ethylene glycol ester of salicyclic acid (beta-, hydroxyethyl salicylate) in 265 grams-of acetone was cooled and treated with 28 grams (0.50 mole) of potassium hydroxide and phosgene as in Example 1 Upon completion of the reaction, the solution was diluted with ice water, whereupon the carbonate of beta-hydroxyethyl salicylate separated out of solution as a white crystalline with water, and recrystallized from ethanol. The recrystallized product had a melting point of approximately 84 C. The-carbonate of betahydroxyethyl salicylate has the formula:

l H H no-omom-o-o o-o-cmcm-on Eatample 4 A solution of 119 grams (0.50 mole) of betabutoxyethyl salicylatein acetone was cooled and treated with 28 grams (0.50 mole) of potassium The reacted mixture was diluted with water, extracted with ben zene, washed, and dried over calcium chloride. Benzene was removed by distillation, and the carbonate wasdistilled under vacuum. There was obtained the carbonate of beta-butoxyethyl salicylate, a colorless, viscous oil, distilling at approximately 275 C. under 3 millimeters pressure, and having a specific gravity of 1.1413 at v -n%, =1.5172 The carbonate of beta-butoxyethyl salicylate has the formula:

Example 5 y grams of beta-ethoxyethyl -hydroxybenzoatewas dissolved in 210 grams of acetone and treated with phosgene and a concentrated p0 tassium hydroxide solution as in Example 1.

During addition of the phosgene, a white, crystalline product separated out of solution. The reaction mixture was diluted with ice water and the solid. product filtered off and recrystallized from ethanol. The recrystallized carbonate of beta-ethoxyethyl l-hyclroxybenzoate was a white, wax-like solid, melting at approximately 46-48 C. and havingthe formula:

' if i i sim-o-omom-o-C o C-O-CHz.CHz-O-C2H5 the methyl ether of tetramethylen'e glycol, betahexoxyethyl salicylate, the S-hydroxybenzoate of thepropyl ether of tetra'ethylene glycol, the i-hydroxybenzoate of the lauryl ether of ethylene glycol, gamma-hydroxypropyl 3-hydroxybenzoate, beta-propoxyethoxyethyl 4-'hydroxybenzoate; etc. I

Other modes of applying the principle of our invention may be employed instead of those explained, change being made as regards the materials employed, provided the products stated by any of the following claims or the'equivalent of any such stated products be employed.

We therefore particularly point out and disf.

tinctly claim as .our invention:

1. A carbonate of an ester. of an hydroxy benzoic acid having the general formula:

wherein R, representsan alkylene radical containing at least 2 carbon atoms, R represents a substituent selected from the class consisting of hydrogen and alkyl radicals, and n represents an integer. 1 i

2. A carbonate of an ester of an hydroxybenzoic acid having the general formula:

wherein R represents an alkylene radical containing at least 2. carbon atoms, and n represents an integer.

3. A carbonate of an ester of an hydroxybenzoic acid having the general formula:

5. The carbonate of the beta-ethoxyethyl ester of salicylic acid, a colorless liquid having a speciflc gravity of 1.2124 at 20/20 C., an index of 15 retraction and having the formula:

6. The carbonate of the beta-butoxyethyl ester of salicyclic acid, a colorless, viscous liquid distilling at approximately 275 C. under 3 millimeters pressure, and having a specific gravity of 1.1413

at 20/40" 0., and the formula:

ERNEST F. GRETHER. RUSSELL B. DU VALL. 

